1. Field of the Invention
The present invention relates to an apparatus and a method for transmitting wireless power, and more particularly, to an apparatus and a method for effectively transmitting wireless power, which control power signal transmission by detecting level changes in preamble signals that are not amplified with power on respective paths of a coil array block having a plurality of transmission coil arrays.
2. Description of the Related Art
Although wireless communication technology has undergone remarkable progress, there is still a need for development. In the case of representative cellular phones in an Information Technology (IT) field, information may be freely and wirelessly delivered, however, its power source still supplies power in a wired manner or through a charged battery. Wireless charging technology has been developed, but still remains at an insignificant level.
Wireless power transmission technology includes electromagnetic induction and magnetic resonance. In the electromagnetic induction method, a power transmission coil and a power reception coil are inductively coupled to each other with a distance of several millimeters (mm) therebetween to deliver energy by means of electromagnetic induction. The electromagnetic induction method may be applied to electric toothbrushes, cellular phone chargers or the like as products that are already put into practical use. In the magnetic resonance method, two dielectric resonators or coil resonators having the same resonance frequency are disposed close to each other to wirelessly transmit the power by means of resonance. This method has developed at a slower pace than the electromagnetic induction method.
In wireless charging systems using the conventional wireless power transmission technology, in order to enhance the efficiency of the system having a multi-coil array structure where multi-charging can be performed, the power is transmitted to the coils where power receiving apparatuses are present by determining the presence of the power receiving apparatuses. Here, determining the presence of the power receiving apparatuses may include receiving a feedback response from a battery being charged by sequentially driving the transmission coils.
Since this method sequentially drives the transmission coils, a delay time increases when several coils are sequentially sensed in the case of the multi-coil array.
In addition, all transmission coils are sequentially driven in order to determine the presence of the power receiving apparatuses, and a great deal of power must be consumed to recognize the presence of the power receiving apparatuses.
Further, in order to make a determination from the received feedback response from the battery being charged, separate communication means for communicating with the battery may be required.